K N Bachus — Page 3 | Search PubMed

PubMedDate not supplied

The effect of reconstruction of the medial patellofemoral ligament on patellar tracking.

We evaluated patellar tracking in six cadaveric knees with the medial restraints intact and then sectioned to determine their contribution to lateral translation of the patella with and without a lateral force on the patella. The medial patellofemoral ligament was then reconstructed with a gracilis tendon graft and patellar tracking was again evaluated. The knees were extended using a materials testing machine, and patellar tracking was measured with a position sensing system. With no lateral force applied to the patella, patellar tracking was unaffected by the presence or absence of the medial restraints or by reconstruction of the medial patellofemoral ligament. With a lateral force applied to the patella, patellar tracking was changed significantly by the loss of the medial restraints. Normal patellar tracking was substantially restored by reconstruction of the medial patellofemoral ligament.

Adult↗

PubMedDate not supplied

Soft tissue restraints to lateral patellar translation in the human knee.

The purpose of this investigation was to identify and quantify the soft tissue restraints, both medially and laterally, to lateral patellar translation. These restraints to lateral patellar translation at 20 degrees of knee flexion were tested biomechanically on a universal testing instrument in nine fresh-frozen cadaveric knees. After preconditioning the tissues, the patella of each intact knee was translated laterally to a distance at which a force of 200 N was recorded. This distance was used to translate the patella for the remaining structures to be sectioned. The contribution of each structure to the total restraining force was determined as the percent of the force to restrain the intact specimen by sectioning the restraints in a predetermined order. The contribution of each structure to the restraining force was defined as the difference between the restraining force before and after its sectioning. The medial patellofemoral ligament was found to be the primary restraint to lateral patellar translation at 20 degrees of flexion, contributing 60% of the total restraining force. The medial patellomeniscal ligament contributed 13% of the total force, and the lateral retinaculum contributed 10%. The medial patellotibial ligament and superficial fibers of the medial retinaculum were not functionally important in preventing lateral translation. The previously unrecognized contribution of the lateral retinaculum as a restraint to lateral patellar translation may shed new light on the failures of isolated lateral release for acute lateral dislocation of the patella.

Adult↗